1 /*- 2 * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) 3 * 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * The Mach Operating System project at Carnegie-Mellon University. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * 35 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 36 * All rights reserved. 37 * 38 * Authors: Avadis Tevanian, Jr., Michael Wayne Young 39 * 40 * Permission to use, copy, modify and distribute this software and 41 * its documentation is hereby granted, provided that both the copyright 42 * notice and this permission notice appear in all copies of the 43 * software, derivative works or modified versions, and any portions 44 * thereof, and that both notices appear in supporting documentation. 45 * 46 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 47 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 48 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 49 * 50 * Carnegie Mellon requests users of this software to return to 51 * 52 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 53 * School of Computer Science 54 * Carnegie Mellon University 55 * Pittsburgh PA 15213-3890 56 * 57 * any improvements or extensions that they make and grant Carnegie the 58 * rights to redistribute these changes. 59 */ 60 61 /* 62 * Virtual memory object module. 63 */ 64 65 #include "opt_vm.h" 66 67 #include <sys/systm.h> 68 #include <sys/blockcount.h> 69 #include <sys/conf.h> 70 #include <sys/cpuset.h> 71 #include <sys/ipc.h> 72 #include <sys/jail.h> 73 #include <sys/limits.h> 74 #include <sys/lock.h> 75 #include <sys/mman.h> 76 #include <sys/mount.h> 77 #include <sys/kernel.h> 78 #include <sys/mutex.h> 79 #include <sys/pctrie.h> 80 #include <sys/proc.h> 81 #include <sys/refcount.h> 82 #include <sys/shm.h> 83 #include <sys/sx.h> 84 #include <sys/sysctl.h> 85 #include <sys/resourcevar.h> 86 #include <sys/refcount.h> 87 #include <sys/rwlock.h> 88 #include <sys/user.h> 89 #include <sys/vnode.h> 90 #include <sys/vmmeter.h> 91 92 #include <vm/vm.h> 93 #include <vm/vm_param.h> 94 #include <vm/pmap.h> 95 #include <vm/vm_map.h> 96 #include <vm/vm_object.h> 97 #include <vm/vm_page.h> 98 #include <vm/vm_pageout.h> 99 #include <vm/vm_pager.h> 100 #include <vm/vm_phys.h> 101 #include <vm/vm_pagequeue.h> 102 #include <vm/swap_pager.h> 103 #include <vm/vm_kern.h> 104 #include <vm/vm_extern.h> 105 #include <vm/vm_radix.h> 106 #include <vm/vm_reserv.h> 107 #include <vm/uma.h> 108 109 static int old_msync; 110 SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, 111 "Use old (insecure) msync behavior"); 112 113 static int vm_object_page_collect_flush(struct pctrie_iter *pages, 114 vm_page_t p, int pagerflags, int flags, boolean_t *allclean, 115 boolean_t *eio); 116 static boolean_t vm_object_page_remove_write(vm_page_t p, int flags, 117 boolean_t *allclean); 118 static void vm_object_backing_remove(vm_object_t object); 119 120 /* 121 * Virtual memory objects maintain the actual data 122 * associated with allocated virtual memory. A given 123 * page of memory exists within exactly one object. 124 * 125 * An object is only deallocated when all "references" 126 * are given up. Only one "reference" to a given 127 * region of an object should be writeable. 128 * 129 * Associated with each object is a list of all resident 130 * memory pages belonging to that object; this list is 131 * maintained by the "vm_page" module, and locked by the object's 132 * lock. 133 * 134 * Each object also records a "pager" routine which is 135 * used to retrieve (and store) pages to the proper backing 136 * storage. In addition, objects may be backed by other 137 * objects from which they were virtual-copied. 138 * 139 * The only items within the object structure which are 140 * modified after time of creation are: 141 * reference count locked by object's lock 142 * pager routine locked by object's lock 143 * 144 */ 145 146 struct object_q vm_object_list; 147 struct mtx vm_object_list_mtx; /* lock for object list and count */ 148 149 struct vm_object kernel_object_store; 150 151 static SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 152 "VM object stats"); 153 154 static COUNTER_U64_DEFINE_EARLY(object_collapses); 155 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, 156 &object_collapses, 157 "VM object collapses"); 158 159 static COUNTER_U64_DEFINE_EARLY(object_bypasses); 160 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, 161 &object_bypasses, 162 "VM object bypasses"); 163 164 static COUNTER_U64_DEFINE_EARLY(object_collapse_waits); 165 SYSCTL_COUNTER_U64(_vm_stats_object, OID_AUTO, collapse_waits, CTLFLAG_RD, 166 &object_collapse_waits, 167 "Number of sleeps for collapse"); 168 169 static uma_zone_t obj_zone; 170 171 static int vm_object_zinit(void *mem, int size, int flags); 172 173 #ifdef INVARIANTS 174 static void vm_object_zdtor(void *mem, int size, void *arg); 175 176 static void 177 vm_object_zdtor(void *mem, int size, void *arg) 178 { 179 vm_object_t object; 180 181 object = (vm_object_t)mem; 182 KASSERT(object->ref_count == 0, 183 ("object %p ref_count = %d", object, object->ref_count)); 184 KASSERT(TAILQ_EMPTY(&object->memq), 185 ("object %p has resident pages in its memq", object)); 186 KASSERT(vm_radix_is_empty(&object->rtree), 187 ("object %p has resident pages in its trie", object)); 188 #if VM_NRESERVLEVEL > 0 189 KASSERT(LIST_EMPTY(&object->rvq), 190 ("object %p has reservations", 191 object)); 192 #endif 193 KASSERT(!vm_object_busied(object), 194 ("object %p busy = %d", object, blockcount_read(&object->busy))); 195 KASSERT(object->resident_page_count == 0, 196 ("object %p resident_page_count = %d", 197 object, object->resident_page_count)); 198 KASSERT(atomic_load_int(&object->shadow_count) == 0, 199 ("object %p shadow_count = %d", 200 object, atomic_load_int(&object->shadow_count))); 201 KASSERT(object->type == OBJT_DEAD, 202 ("object %p has non-dead type %d", 203 object, object->type)); 204 KASSERT(object->charge == 0 && object->cred == NULL, 205 ("object %p has non-zero charge %ju (%p)", 206 object, (uintmax_t)object->charge, object->cred)); 207 } 208 #endif 209 210 static int 211 vm_object_zinit(void *mem, int size, int flags) 212 { 213 vm_object_t object; 214 215 object = (vm_object_t)mem; 216 rw_init_flags(&object->lock, "vmobject", RW_DUPOK | RW_NEW); 217 218 /* These are true for any object that has been freed */ 219 object->type = OBJT_DEAD; 220 vm_radix_init(&object->rtree); 221 refcount_init(&object->ref_count, 0); 222 blockcount_init(&object->paging_in_progress); 223 blockcount_init(&object->busy); 224 object->resident_page_count = 0; 225 atomic_store_int(&object->shadow_count, 0); 226 object->flags = OBJ_DEAD; 227 228 mtx_lock(&vm_object_list_mtx); 229 TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); 230 mtx_unlock(&vm_object_list_mtx); 231 return (0); 232 } 233 234 static void 235 _vm_object_allocate(objtype_t type, vm_pindex_t size, u_short flags, 236 vm_object_t object, void *handle) 237 { 238 239 TAILQ_INIT(&object->memq); 240 LIST_INIT(&object->shadow_head); 241 242 object->type = type; 243 object->flags = flags; 244 if ((flags & OBJ_SWAP) != 0) { 245 pctrie_init(&object->un_pager.swp.swp_blks); 246 object->un_pager.swp.writemappings = 0; 247 } 248 249 /* 250 * Ensure that swap_pager_swapoff() iteration over object_list 251 * sees up to date type and pctrie head if it observed 252 * non-dead object. 253 */ 254 atomic_thread_fence_rel(); 255 256 object->pg_color = 0; 257 object->size = size; 258 object->domain.dr_policy = NULL; 259 object->generation = 1; 260 object->cleangeneration = 1; 261 refcount_init(&object->ref_count, 1); 262 object->memattr = VM_MEMATTR_DEFAULT; 263 object->cred = NULL; 264 object->charge = 0; 265 object->handle = handle; 266 object->backing_object = NULL; 267 object->backing_object_offset = (vm_ooffset_t) 0; 268 #if VM_NRESERVLEVEL > 0 269 LIST_INIT(&object->rvq); 270 #endif 271 umtx_shm_object_init(object); 272 } 273 274 /* 275 * vm_object_init: 276 * 277 * Initialize the VM objects module. 278 */ 279 void 280 vm_object_init(void) 281 { 282 TAILQ_INIT(&vm_object_list); 283 mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); 284 285 rw_init(&kernel_object->lock, "kernel vm object"); 286 vm_radix_init(&kernel_object->rtree); 287 _vm_object_allocate(OBJT_PHYS, atop(VM_MAX_KERNEL_ADDRESS - 288 VM_MIN_KERNEL_ADDRESS), OBJ_UNMANAGED, kernel_object, NULL); 289 #if VM_NRESERVLEVEL > 0 290 kernel_object->flags |= OBJ_COLORED; 291 kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); 292 #endif 293 kernel_object->un_pager.phys.ops = &default_phys_pg_ops; 294 295 /* 296 * The lock portion of struct vm_object must be type stable due 297 * to vm_pageout_fallback_object_lock locking a vm object 298 * without holding any references to it. 299 * 300 * paging_in_progress is valid always. Lockless references to 301 * the objects may acquire pip and then check OBJ_DEAD. 302 */ 303 obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, 304 #ifdef INVARIANTS 305 vm_object_zdtor, 306 #else 307 NULL, 308 #endif 309 vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_NOFREE); 310 311 vm_radix_zinit(); 312 } 313 314 void 315 vm_object_clear_flag(vm_object_t object, u_short bits) 316 { 317 318 VM_OBJECT_ASSERT_WLOCKED(object); 319 object->flags &= ~bits; 320 } 321 322 /* 323 * Sets the default memory attribute for the specified object. Pages 324 * that are allocated to this object are by default assigned this memory 325 * attribute. 326 * 327 * Presently, this function must be called before any pages are allocated 328 * to the object. In the future, this requirement may be relaxed for 329 * "default" and "swap" objects. 330 */ 331 int 332 vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) 333 { 334 335 VM_OBJECT_ASSERT_WLOCKED(object); 336 337 if (object->type == OBJT_DEAD) 338 return (KERN_INVALID_ARGUMENT); 339 if (!vm_radix_is_empty(&object->rtree)) 340 return (KERN_FAILURE); 341 342 object->memattr = memattr; 343 return (KERN_SUCCESS); 344 } 345 346 void 347 vm_object_pip_add(vm_object_t object, short i) 348 { 349 350 if (i > 0) 351 blockcount_acquire(&object->paging_in_progress, i); 352 } 353 354 void 355 vm_object_pip_wakeup(vm_object_t object) 356 { 357 358 vm_object_pip_wakeupn(object, 1); 359 } 360 361 void 362 vm_object_pip_wakeupn(vm_object_t object, short i) 363 { 364 365 if (i > 0) 366 blockcount_release(&object->paging_in_progress, i); 367 } 368 369 /* 370 * Atomically drop the object lock and wait for pip to drain. This protects 371 * from sleep/wakeup races due to identity changes. The lock is not re-acquired 372 * on return. 373 */ 374 static void 375 vm_object_pip_sleep(vm_object_t object, const char *waitid) 376 { 377 378 (void)blockcount_sleep(&object->paging_in_progress, &object->lock, 379 waitid, PVM | PDROP); 380 } 381 382 void 383 vm_object_pip_wait(vm_object_t object, const char *waitid) 384 { 385 386 VM_OBJECT_ASSERT_WLOCKED(object); 387 388 blockcount_wait(&object->paging_in_progress, &object->lock, waitid, 389 PVM); 390 } 391 392 void 393 vm_object_pip_wait_unlocked(vm_object_t object, const char *waitid) 394 { 395 396 VM_OBJECT_ASSERT_UNLOCKED(object); 397 398 blockcount_wait(&object->paging_in_progress, NULL, waitid, PVM); 399 } 400 401 /* 402 * vm_object_allocate: 403 * 404 * Returns a new object with the given size. 405 */ 406 vm_object_t 407 vm_object_allocate(objtype_t type, vm_pindex_t size) 408 { 409 vm_object_t object; 410 u_short flags; 411 412 switch (type) { 413 case OBJT_DEAD: 414 panic("vm_object_allocate: can't create OBJT_DEAD"); 415 case OBJT_SWAP: 416 flags = OBJ_COLORED | OBJ_SWAP; 417 break; 418 case OBJT_DEVICE: 419 case OBJT_SG: 420 flags = OBJ_FICTITIOUS | OBJ_UNMANAGED; 421 break; 422 case OBJT_MGTDEVICE: 423 flags = OBJ_FICTITIOUS; 424 break; 425 case OBJT_PHYS: 426 flags = OBJ_UNMANAGED; 427 break; 428 case OBJT_VNODE: 429 flags = 0; 430 break; 431 default: 432 panic("vm_object_allocate: type %d is undefined or dynamic", 433 type); 434 } 435 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 436 _vm_object_allocate(type, size, flags, object, NULL); 437 438 return (object); 439 } 440 441 vm_object_t 442 vm_object_allocate_dyn(objtype_t dyntype, vm_pindex_t size, u_short flags) 443 { 444 vm_object_t object; 445 446 MPASS(dyntype >= OBJT_FIRST_DYN /* && dyntype < nitems(pagertab) */); 447 object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); 448 _vm_object_allocate(dyntype, size, flags, object, NULL); 449 450 return (object); 451 } 452 453 /* 454 * vm_object_allocate_anon: 455 * 456 * Returns a new default object of the given size and marked as 457 * anonymous memory for special split/collapse handling. Color 458 * to be initialized by the caller. 459 */ 460 vm_object_t 461 vm_object_allocate_anon(vm_pindex_t size, vm_object_t backing_object, 462 struct ucred *cred, vm_size_t charge) 463 { 464 vm_object_t handle, object; 465 466 if (backing_object == NULL) 467 handle = NULL; 468 else if ((backing_object->flags & OBJ_ANON) != 0) 469 handle = backing_object->handle; 470 else 471 handle = backing_object; 472 object = uma_zalloc(obj_zone, M_WAITOK); 473 _vm_object_allocate(OBJT_SWAP, size, 474 OBJ_ANON | OBJ_ONEMAPPING | OBJ_SWAP, object, handle); 475 object->cred = cred; 476 object->charge = cred != NULL ? charge : 0; 477 return (object); 478 } 479 480 static void 481 vm_object_reference_vnode(vm_object_t object) 482 { 483 u_int old; 484 485 /* 486 * vnode objects need the lock for the first reference 487 * to serialize with vnode_object_deallocate(). 488 */ 489 if (!refcount_acquire_if_gt(&object->ref_count, 0)) { 490 VM_OBJECT_RLOCK(object); 491 old = refcount_acquire(&object->ref_count); 492 if (object->type == OBJT_VNODE && old == 0) 493 vref(object->handle); 494 VM_OBJECT_RUNLOCK(object); 495 } 496 } 497 498 /* 499 * vm_object_reference: 500 * 501 * Acquires a reference to the given object. 502 */ 503 void 504 vm_object_reference(vm_object_t object) 505 { 506 507 if (object == NULL) 508 return; 509 510 if (object->type == OBJT_VNODE) 511 vm_object_reference_vnode(object); 512 else 513 refcount_acquire(&object->ref_count); 514 KASSERT((object->flags & OBJ_DEAD) == 0, 515 ("vm_object_reference: Referenced dead object.")); 516 } 517 518 /* 519 * vm_object_reference_locked: 520 * 521 * Gets another reference to the given object. 522 * 523 * The object must be locked. 524 */ 525 void 526 vm_object_reference_locked(vm_object_t object) 527 { 528 u_int old; 529 530 VM_OBJECT_ASSERT_LOCKED(object); 531 old = refcount_acquire(&object->ref_count); 532 if (object->type == OBJT_VNODE && old == 0) 533 vref(object->handle); 534 KASSERT((object->flags & OBJ_DEAD) == 0, 535 ("vm_object_reference: Referenced dead object.")); 536 } 537 538 /* 539 * Handle deallocating an object of type OBJT_VNODE. 540 */ 541 static void 542 vm_object_deallocate_vnode(vm_object_t object) 543 { 544 struct vnode *vp = (struct vnode *) object->handle; 545 bool last; 546 547 KASSERT(object->type == OBJT_VNODE, 548 ("vm_object_deallocate_vnode: not a vnode object")); 549 KASSERT(vp != NULL, ("vm_object_deallocate_vnode: missing vp")); 550 551 /* Object lock to protect handle lookup. */ 552 last = refcount_release(&object->ref_count); 553 VM_OBJECT_RUNLOCK(object); 554 555 if (!last) 556 return; 557 558 if (!umtx_shm_vnobj_persistent) 559 umtx_shm_object_terminated(object); 560 561 /* vrele may need the vnode lock. */ 562 vrele(vp); 563 } 564 565 /* 566 * We dropped a reference on an object and discovered that it had a 567 * single remaining shadow. This is a sibling of the reference we 568 * dropped. Attempt to collapse the sibling and backing object. 569 */ 570 static vm_object_t 571 vm_object_deallocate_anon(vm_object_t backing_object) 572 { 573 vm_object_t object; 574 575 /* Fetch the final shadow. */ 576 object = LIST_FIRST(&backing_object->shadow_head); 577 KASSERT(object != NULL && 578 atomic_load_int(&backing_object->shadow_count) == 1, 579 ("vm_object_anon_deallocate: ref_count: %d, shadow_count: %d", 580 backing_object->ref_count, 581 atomic_load_int(&backing_object->shadow_count))); 582 KASSERT((object->flags & OBJ_ANON) != 0, 583 ("invalid shadow object %p", object)); 584 585 if (!VM_OBJECT_TRYWLOCK(object)) { 586 /* 587 * Prevent object from disappearing since we do not have a 588 * reference. 589 */ 590 vm_object_pip_add(object, 1); 591 VM_OBJECT_WUNLOCK(backing_object); 592 VM_OBJECT_WLOCK(object); 593 vm_object_pip_wakeup(object); 594 } else 595 VM_OBJECT_WUNLOCK(backing_object); 596 597 /* 598 * Check for a collapse/terminate race with the last reference holder. 599 */ 600 if ((object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) != 0 || 601 !refcount_acquire_if_not_zero(&object->ref_count)) { 602 VM_OBJECT_WUNLOCK(object); 603 return (NULL); 604 } 605 backing_object = object->backing_object; 606 if (backing_object != NULL && (backing_object->flags & OBJ_ANON) != 0) 607 vm_object_collapse(object); 608 VM_OBJECT_WUNLOCK(object); 609 610 return (object); 611 } 612 613 /* 614 * vm_object_deallocate: 615 * 616 * Release a reference to the specified object, 617 * gained either through a vm_object_allocate 618 * or a vm_object_reference call. When all references 619 * are gone, storage associated with this object 620 * may be relinquished. 621 * 622 * No object may be locked. 623 */ 624 void 625 vm_object_deallocate(vm_object_t object) 626 { 627 vm_object_t temp; 628 bool released; 629 630 while (object != NULL) { 631 /* 632 * If the reference count goes to 0 we start calling 633 * vm_object_terminate() on the object chain. A ref count 634 * of 1 may be a special case depending on the shadow count 635 * being 0 or 1. These cases require a write lock on the 636 * object. 637 */ 638 if ((object->flags & OBJ_ANON) == 0) 639 released = refcount_release_if_gt(&object->ref_count, 1); 640 else 641 released = refcount_release_if_gt(&object->ref_count, 2); 642 if (released) 643 return; 644 645 if (object->type == OBJT_VNODE) { 646 VM_OBJECT_RLOCK(object); 647 if (object->type == OBJT_VNODE) { 648 vm_object_deallocate_vnode(object); 649 return; 650 } 651 VM_OBJECT_RUNLOCK(object); 652 } 653 654 VM_OBJECT_WLOCK(object); 655 KASSERT(object->ref_count > 0, 656 ("vm_object_deallocate: object deallocated too many times: %d", 657 object->type)); 658 659 /* 660 * If this is not the final reference to an anonymous 661 * object we may need to collapse the shadow chain. 662 */ 663 if (!refcount_release(&object->ref_count)) { 664 if (object->ref_count > 1 || 665 atomic_load_int(&object->shadow_count) == 0) { 666 if ((object->flags & OBJ_ANON) != 0 && 667 object->ref_count == 1) 668 vm_object_set_flag(object, 669 OBJ_ONEMAPPING); 670 VM_OBJECT_WUNLOCK(object); 671 return; 672 } 673 674 /* Handle collapsing last ref on anonymous objects. */ 675 object = vm_object_deallocate_anon(object); 676 continue; 677 } 678 679 /* 680 * Handle the final reference to an object. We restart 681 * the loop with the backing object to avoid recursion. 682 */ 683 umtx_shm_object_terminated(object); 684 temp = object->backing_object; 685 if (temp != NULL) { 686 KASSERT(object->type == OBJT_SWAP, 687 ("shadowed tmpfs v_object 2 %p", object)); 688 vm_object_backing_remove(object); 689 } 690 691 KASSERT((object->flags & OBJ_DEAD) == 0, 692 ("vm_object_deallocate: Terminating dead object.")); 693 vm_object_set_flag(object, OBJ_DEAD); 694 vm_object_terminate(object); 695 object = temp; 696 } 697 } 698 699 void 700 vm_object_destroy(vm_object_t object) 701 { 702 uma_zfree(obj_zone, object); 703 } 704 705 static void 706 vm_object_sub_shadow(vm_object_t object) 707 { 708 KASSERT(object->shadow_count >= 1, 709 ("object %p sub_shadow count zero", object)); 710 atomic_subtract_int(&object->shadow_count, 1); 711 } 712 713 static void 714 vm_object_backing_remove_locked(vm_object_t object) 715 { 716 vm_object_t backing_object; 717 718 backing_object = object->backing_object; 719 VM_OBJECT_ASSERT_WLOCKED(object); 720 VM_OBJECT_ASSERT_WLOCKED(backing_object); 721 722 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 723 ("vm_object_backing_remove: Removing collapsing object.")); 724 725 vm_object_sub_shadow(backing_object); 726 if ((object->flags & OBJ_SHADOWLIST) != 0) { 727 LIST_REMOVE(object, shadow_list); 728 vm_object_clear_flag(object, OBJ_SHADOWLIST); 729 } 730 object->backing_object = NULL; 731 } 732 733 static void 734 vm_object_backing_remove(vm_object_t object) 735 { 736 vm_object_t backing_object; 737 738 VM_OBJECT_ASSERT_WLOCKED(object); 739 740 backing_object = object->backing_object; 741 if ((object->flags & OBJ_SHADOWLIST) != 0) { 742 VM_OBJECT_WLOCK(backing_object); 743 vm_object_backing_remove_locked(object); 744 VM_OBJECT_WUNLOCK(backing_object); 745 } else { 746 object->backing_object = NULL; 747 vm_object_sub_shadow(backing_object); 748 } 749 } 750 751 static void 752 vm_object_backing_insert_locked(vm_object_t object, vm_object_t backing_object) 753 { 754 755 VM_OBJECT_ASSERT_WLOCKED(object); 756 757 atomic_add_int(&backing_object->shadow_count, 1); 758 if ((backing_object->flags & OBJ_ANON) != 0) { 759 VM_OBJECT_ASSERT_WLOCKED(backing_object); 760 LIST_INSERT_HEAD(&backing_object->shadow_head, object, 761 shadow_list); 762 vm_object_set_flag(object, OBJ_SHADOWLIST); 763 } 764 object->backing_object = backing_object; 765 } 766 767 static void 768 vm_object_backing_insert(vm_object_t object, vm_object_t backing_object) 769 { 770 771 VM_OBJECT_ASSERT_WLOCKED(object); 772 773 if ((backing_object->flags & OBJ_ANON) != 0) { 774 VM_OBJECT_WLOCK(backing_object); 775 vm_object_backing_insert_locked(object, backing_object); 776 VM_OBJECT_WUNLOCK(backing_object); 777 } else { 778 object->backing_object = backing_object; 779 atomic_add_int(&backing_object->shadow_count, 1); 780 } 781 } 782 783 /* 784 * Insert an object into a backing_object's shadow list with an additional 785 * reference to the backing_object added. 786 */ 787 static void 788 vm_object_backing_insert_ref(vm_object_t object, vm_object_t backing_object) 789 { 790 791 VM_OBJECT_ASSERT_WLOCKED(object); 792 793 if ((backing_object->flags & OBJ_ANON) != 0) { 794 VM_OBJECT_WLOCK(backing_object); 795 KASSERT((backing_object->flags & OBJ_DEAD) == 0, 796 ("shadowing dead anonymous object")); 797 vm_object_reference_locked(backing_object); 798 vm_object_backing_insert_locked(object, backing_object); 799 vm_object_clear_flag(backing_object, OBJ_ONEMAPPING); 800 VM_OBJECT_WUNLOCK(backing_object); 801 } else { 802 vm_object_reference(backing_object); 803 atomic_add_int(&backing_object->shadow_count, 1); 804 object->backing_object = backing_object; 805 } 806 } 807 808 /* 809 * Transfer a backing reference from backing_object to object. 810 */ 811 static void 812 vm_object_backing_transfer(vm_object_t object, vm_object_t backing_object) 813 { 814 vm_object_t new_backing_object; 815 816 /* 817 * Note that the reference to backing_object->backing_object 818 * moves from within backing_object to within object. 819 */ 820 vm_object_backing_remove_locked(object); 821 new_backing_object = backing_object->backing_object; 822 if (new_backing_object == NULL) 823 return; 824 if ((new_backing_object->flags & OBJ_ANON) != 0) { 825 VM_OBJECT_WLOCK(new_backing_object); 826 vm_object_backing_remove_locked(backing_object); 827 vm_object_backing_insert_locked(object, new_backing_object); 828 VM_OBJECT_WUNLOCK(new_backing_object); 829 } else { 830 /* 831 * shadow_count for new_backing_object is left 832 * unchanged, its reference provided by backing_object 833 * is replaced by object. 834 */ 835 object->backing_object = new_backing_object; 836 backing_object->backing_object = NULL; 837 } 838 } 839 840 /* 841 * Wait for a concurrent collapse to settle. 842 */ 843 static void 844 vm_object_collapse_wait(vm_object_t object) 845 { 846 847 VM_OBJECT_ASSERT_WLOCKED(object); 848 849 while ((object->flags & OBJ_COLLAPSING) != 0) { 850 vm_object_pip_wait(object, "vmcolwait"); 851 counter_u64_add(object_collapse_waits, 1); 852 } 853 } 854 855 /* 856 * Waits for a backing object to clear a pending collapse and returns 857 * it locked if it is an ANON object. 858 */ 859 static vm_object_t 860 vm_object_backing_collapse_wait(vm_object_t object) 861 { 862 vm_object_t backing_object; 863 864 VM_OBJECT_ASSERT_WLOCKED(object); 865 866 for (;;) { 867 backing_object = object->backing_object; 868 if (backing_object == NULL || 869 (backing_object->flags & OBJ_ANON) == 0) 870 return (NULL); 871 VM_OBJECT_WLOCK(backing_object); 872 if ((backing_object->flags & (OBJ_DEAD | OBJ_COLLAPSING)) == 0) 873 break; 874 VM_OBJECT_WUNLOCK(object); 875 vm_object_pip_sleep(backing_object, "vmbckwait"); 876 counter_u64_add(object_collapse_waits, 1); 877 VM_OBJECT_WLOCK(object); 878 } 879 return (backing_object); 880 } 881 882 /* 883 * vm_object_terminate_single_page removes a pageable page from the object, 884 * and removes it from the paging queues and frees it, if it is not wired. 885 * It is invoked via callback from vm_object_terminate_pages. 886 */ 887 static void 888 vm_object_terminate_single_page(vm_page_t p, void *objectv) 889 { 890 vm_object_t object __diagused = objectv; 891 892 vm_page_assert_unbusied(p); 893 KASSERT(p->object == object && 894 (p->ref_count & VPRC_OBJREF) != 0, 895 ("%s: page %p is inconsistent", __func__, p)); 896 p->object = NULL; 897 if (vm_page_drop(p, VPRC_OBJREF) == VPRC_OBJREF) { 898 KASSERT((object->flags & OBJ_UNMANAGED) != 0 || 899 vm_page_astate_load(p).queue != PQ_NONE, 900 ("%s: page %p does not belong to a queue", __func__, p)); 901 VM_CNT_INC(v_pfree); 902 vm_page_free(p); 903 } 904 } 905 906 /* 907 * vm_object_terminate_pages removes any remaining pageable pages 908 * from the object and resets the object to an empty state. 909 */ 910 static void 911 vm_object_terminate_pages(vm_object_t object) 912 { 913 VM_OBJECT_ASSERT_WLOCKED(object); 914 915 /* 916 * If the object contained any pages, then reset it to an empty state. 917 * Rather than incrementally removing each page from the object, the 918 * page and object are reset to any empty state. 919 */ 920 if (object->resident_page_count == 0) 921 return; 922 923 vm_radix_reclaim_callback(&object->rtree, 924 vm_object_terminate_single_page, object); 925 TAILQ_INIT(&object->memq); 926 object->resident_page_count = 0; 927 if (object->type == OBJT_VNODE) 928 vdrop(object->handle); 929 } 930 931 /* 932 * vm_object_terminate actually destroys the specified object, freeing 933 * up all previously used resources. 934 * 935 * The object must be locked. 936 * This routine may block. 937 */ 938 void 939 vm_object_terminate(vm_object_t object) 940 { 941 942 VM_OBJECT_ASSERT_WLOCKED(object); 943 KASSERT((object->flags & OBJ_DEAD) != 0, 944 ("terminating non-dead obj %p", object)); 945 KASSERT((object->flags & OBJ_COLLAPSING) == 0, 946 ("terminating collapsing obj %p", object)); 947 KASSERT(object->backing_object == NULL, 948 ("terminating shadow obj %p", object)); 949 950 /* 951 * Wait for the pageout daemon and other current users to be 952 * done with the object. Note that new paging_in_progress 953 * users can come after this wait, but they must check 954 * OBJ_DEAD flag set (without unlocking the object), and avoid 955 * the object being terminated. 956 */ 957 vm_object_pip_wait(object, "objtrm"); 958 959 KASSERT(object->ref_count == 0, 960 ("vm_object_terminate: object with references, ref_count=%d", 961 object->ref_count)); 962 963 if ((object->flags & OBJ_PG_DTOR) == 0) 964 vm_object_terminate_pages(object); 965 966 #if VM_NRESERVLEVEL > 0 967 if (__predict_false(!LIST_EMPTY(&object->rvq))) 968 vm_reserv_break_all(object); 969 #endif 970 971 KASSERT(object->cred == NULL || (object->flags & OBJ_SWAP) != 0, 972 ("%s: non-swap obj %p has cred", __func__, object)); 973 974 /* 975 * Let the pager know object is dead. 976 */ 977 vm_pager_deallocate(object); 978 VM_OBJECT_WUNLOCK(object); 979 980 vm_object_destroy(object); 981 } 982 983 /* 984 * Make the page read-only so that we can clear the object flags. However, if 985 * this is a nosync mmap then the object is likely to stay dirty so do not 986 * mess with the page and do not clear the object flags. Returns TRUE if the 987 * page should be flushed, and FALSE otherwise. 988 */ 989 static boolean_t 990 vm_object_page_remove_write(vm_page_t p, int flags, boolean_t *allclean) 991 { 992 993 vm_page_assert_busied(p); 994 995 /* 996 * If we have been asked to skip nosync pages and this is a 997 * nosync page, skip it. Note that the object flags were not 998 * cleared in this case so we do not have to set them. 999 */ 1000 if ((flags & OBJPC_NOSYNC) != 0 && (p->a.flags & PGA_NOSYNC) != 0) { 1001 *allclean = FALSE; 1002 return (FALSE); 1003 } else { 1004 pmap_remove_write(p); 1005 return (p->dirty != 0); 1006 } 1007 } 1008 1009 /* 1010 * vm_object_page_clean 1011 * 1012 * Clean all dirty pages in the specified range of object. Leaves page 1013 * on whatever queue it is currently on. If NOSYNC is set then do not 1014 * write out pages with PGA_NOSYNC set (originally comes from MAP_NOSYNC), 1015 * leaving the object dirty. 1016 * 1017 * For swap objects backing tmpfs regular files, do not flush anything, 1018 * but remove write protection on the mapped pages to update mtime through 1019 * mmaped writes. 1020 * 1021 * When stuffing pages asynchronously, allow clustering. XXX we need a 1022 * synchronous clustering mode implementation. 1023 * 1024 * Odd semantics: if start == end, we clean everything. 1025 * 1026 * The object must be locked. 1027 * 1028 * Returns FALSE if some page from the range was not written, as 1029 * reported by the pager, and TRUE otherwise. 1030 */ 1031 boolean_t 1032 vm_object_page_clean(vm_object_t object, vm_ooffset_t start, vm_ooffset_t end, 1033 int flags) 1034 { 1035 struct pctrie_iter pages; 1036 vm_page_t np, p; 1037 vm_pindex_t pi, tend, tstart; 1038 int curgeneration, n, pagerflags; 1039 boolean_t eio, res, allclean; 1040 1041 VM_OBJECT_ASSERT_WLOCKED(object); 1042 1043 if (!vm_object_mightbedirty(object) || object->resident_page_count == 0) 1044 return (TRUE); 1045 1046 pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) != 0 ? 1047 VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; 1048 pagerflags |= (flags & OBJPC_INVAL) != 0 ? VM_PAGER_PUT_INVAL : 0; 1049 1050 tstart = OFF_TO_IDX(start); 1051 tend = (end == 0) ? object->size : OFF_TO_IDX(end + PAGE_MASK); 1052 allclean = tstart == 0 && tend >= object->size; 1053 res = TRUE; 1054 vm_page_iter_init(&pages, object); 1055 1056 rescan: 1057 curgeneration = object->generation; 1058 1059 for (p = vm_radix_iter_lookup_ge(&pages, tstart); p != NULL; p = np) { 1060 pi = p->pindex; 1061 if (pi >= tend) 1062 break; 1063 if (vm_page_none_valid(p)) { 1064 np = vm_radix_iter_step(&pages); 1065 continue; 1066 } 1067 if (!vm_page_busy_acquire(p, VM_ALLOC_WAITFAIL)) { 1068 pctrie_iter_reset(&pages); 1069 if (object->generation != curgeneration && 1070 (flags & OBJPC_SYNC) != 0) 1071 goto rescan; 1072 np = vm_radix_iter_lookup_ge(&pages, pi); 1073 continue; 1074 } 1075 if (!vm_object_page_remove_write(p, flags, &allclean)) { 1076 np = vm_radix_iter_step(&pages); 1077 vm_page_xunbusy(p); 1078 continue; 1079 } 1080 if (object->type == OBJT_VNODE) { 1081 n = vm_object_page_collect_flush(&pages, p, pagerflags, 1082 flags, &allclean, &eio); 1083 pctrie_iter_reset(&pages); 1084 if (eio) { 1085 res = FALSE; 1086 allclean = FALSE; 1087 } 1088 if (object->generation != curgeneration && 1089 (flags & OBJPC_SYNC) != 0) 1090 goto rescan; 1091 1092 /* 1093 * If the VOP_PUTPAGES() did a truncated write, so 1094 * that even the first page of the run is not fully 1095 * written, vm_pageout_flush() returns 0 as the run 1096 * length. Since the condition that caused truncated 1097 * write may be permanent, e.g. exhausted free space, 1098 * accepting n == 0 would cause an infinite loop. 1099 * 1100 * Forwarding the iterator leaves the unwritten page 1101 * behind, but there is not much we can do there if 1102 * filesystem refuses to write it. 1103 */ 1104 if (n == 0) { 1105 n = 1; 1106 allclean = FALSE; 1107 } 1108 } else { 1109 n = 1; 1110 vm_page_xunbusy(p); 1111 } 1112 np = vm_radix_iter_lookup_ge(&pages, pi + n); 1113 } 1114 #if 0 1115 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC) ? MNT_WAIT : 0); 1116 #endif 1117 1118 /* 1119 * Leave updating cleangeneration for tmpfs objects to tmpfs 1120 * scan. It needs to update mtime, which happens for other 1121 * filesystems during page writeouts. 1122 */ 1123 if (allclean && object->type == OBJT_VNODE) 1124 object->cleangeneration = curgeneration; 1125 return (res); 1126 } 1127 1128 static int 1129 vm_object_page_collect_flush(struct pctrie_iter *pages, vm_page_t p, 1130 int pagerflags, int flags, boolean_t *allclean, boolean_t *eio) 1131 { 1132 vm_page_t ma[2 * vm_pageout_page_count - 1]; 1133 int base, count, runlen; 1134 1135 vm_page_lock_assert(p, MA_NOTOWNED); 1136 vm_page_assert_xbusied(p); 1137 base = nitems(ma) / 2; 1138 ma[base] = p; 1139 for (count = 1; count < vm_pageout_page_count; count++) { 1140 p = vm_radix_iter_next(pages); 1141 if (p == NULL || vm_page_tryxbusy(p) == 0) 1142 break; 1143 if (!vm_object_page_remove_write(p, flags, allclean)) { 1144 vm_page_xunbusy(p); 1145 break; 1146 } 1147 ma[base + count] = p; 1148 } 1149 1150 pages->index = ma[base]->pindex; 1151 for (; count < vm_pageout_page_count; count++) { 1152 p = vm_radix_iter_prev(pages); 1153 if (p == NULL || vm_page_tryxbusy(p) == 0) 1154 break; 1155 if (!vm_object_page_remove_write(p, flags, allclean)) { 1156 vm_page_xunbusy(p); 1157 break; 1158 } 1159 ma[--base] = p; 1160 } 1161 1162 vm_pageout_flush(&ma[base], count, pagerflags, nitems(ma) / 2 - base, 1163 &runlen, eio); 1164 return (runlen); 1165 } 1166 1167 /* 1168 * Note that there is absolutely no sense in writing out 1169 * anonymous objects, so we track down the vnode object 1170 * to write out. 1171 * We invalidate (remove) all pages from the address space 1172 * for semantic correctness. 1173 * 1174 * If the backing object is a device object with unmanaged pages, then any 1175 * mappings to the specified range of pages must be removed before this 1176 * function is called. 1177 * 1178 * Note: certain anonymous maps, such as MAP_NOSYNC maps, 1179 * may start out with a NULL object. 1180 */ 1181 boolean_t 1182 vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, 1183 boolean_t syncio, boolean_t invalidate) 1184 { 1185 vm_object_t backing_object; 1186 struct vnode *vp; 1187 struct mount *mp; 1188 int error, flags, fsync_after; 1189 boolean_t res; 1190 1191 if (object == NULL) 1192 return (TRUE); 1193 res = TRUE; 1194 error = 0; 1195 VM_OBJECT_WLOCK(object); 1196 while ((backing_object = object->backing_object) != NULL) { 1197 VM_OBJECT_WLOCK(backing_object); 1198 offset += object->backing_object_offset; 1199 VM_OBJECT_WUNLOCK(object); 1200 object = backing_object; 1201 if (object->size < OFF_TO_IDX(offset + size)) 1202 size = IDX_TO_OFF(object->size) - offset; 1203 } 1204 /* 1205 * Flush pages if writing is allowed, invalidate them 1206 * if invalidation requested. Pages undergoing I/O 1207 * will be ignored by vm_object_page_remove(). 1208 * 1209 * We cannot lock the vnode and then wait for paging 1210 * to complete without deadlocking against vm_fault. 1211 * Instead we simply call vm_object_page_remove() and 1212 * allow it to block internally on a page-by-page 1213 * basis when it encounters pages undergoing async 1214 * I/O. 1215 */ 1216 if (object->type == OBJT_VNODE && 1217 vm_object_mightbedirty(object) != 0 && 1218 ((vp = object->handle)->v_vflag & VV_NOSYNC) == 0) { 1219 VM_OBJECT_WUNLOCK(object); 1220 (void)vn_start_write(vp, &mp, V_WAIT); 1221 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1222 if (syncio && !invalidate && offset == 0 && 1223 atop(size) == object->size) { 1224 /* 1225 * If syncing the whole mapping of the file, 1226 * it is faster to schedule all the writes in 1227 * async mode, also allowing the clustering, 1228 * and then wait for i/o to complete. 1229 */ 1230 flags = 0; 1231 fsync_after = TRUE; 1232 } else { 1233 flags = (syncio || invalidate) ? OBJPC_SYNC : 0; 1234 flags |= invalidate ? (OBJPC_SYNC | OBJPC_INVAL) : 0; 1235 fsync_after = FALSE; 1236 } 1237 VM_OBJECT_WLOCK(object); 1238 res = vm_object_page_clean(object, offset, offset + size, 1239 flags); 1240 VM_OBJECT_WUNLOCK(object); 1241 if (fsync_after) { 1242 for (;;) { 1243 error = VOP_FSYNC(vp, MNT_WAIT, curthread); 1244 if (error != ERELOOKUP) 1245 break; 1246 1247 /* 1248 * Allow SU/bufdaemon to handle more 1249 * dependencies in the meantime. 1250 */ 1251 VOP_UNLOCK(vp); 1252 vn_finished_write(mp); 1253 1254 (void)vn_start_write(vp, &mp, V_WAIT); 1255 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); 1256 } 1257 } 1258 VOP_UNLOCK(vp); 1259 vn_finished_write(mp); 1260 if (error != 0) 1261 res = FALSE; 1262 VM_OBJECT_WLOCK(object); 1263 } 1264 if ((object->type == OBJT_VNODE || 1265 object->type == OBJT_DEVICE) && invalidate) { 1266 if (object->type == OBJT_DEVICE) 1267 /* 1268 * The option OBJPR_NOTMAPPED must be passed here 1269 * because vm_object_page_remove() cannot remove 1270 * unmanaged mappings. 1271 */ 1272 flags = OBJPR_NOTMAPPED; 1273 else if (old_msync) 1274 flags = 0; 1275 else 1276 flags = OBJPR_CLEANONLY; 1277 vm_object_page_remove(object, OFF_TO_IDX(offset), 1278 OFF_TO_IDX(offset + size + PAGE_MASK), flags); 1279 } 1280 VM_OBJECT_WUNLOCK(object); 1281 return (res); 1282 } 1283 1284 /* 1285 * Determine whether the given advice can be applied to the object. Advice is 1286 * not applied to unmanaged pages since they never belong to page queues, and 1287 * since MADV_FREE is destructive, it can apply only to anonymous pages that 1288 * have been mapped at most once. 1289 */ 1290 static bool 1291 vm_object_advice_applies(vm_object_t object, int advice) 1292 { 1293 1294 if ((object->flags & OBJ_UNMANAGED) != 0) 1295 return (false); 1296 if (advice != MADV_FREE) 1297 return (true); 1298 return ((object->flags & (OBJ_ONEMAPPING | OBJ_ANON)) == 1299 (OBJ_ONEMAPPING | OBJ_ANON)); 1300 } 1301 1302 static void 1303 vm_object_madvise_freespace(vm_object_t object, int advice, vm_pindex_t pindex, 1304 vm_size_t size) 1305 { 1306 1307 if (advice == MADV_FREE) 1308 vm_pager_freespace(object, pindex, size); 1309 } 1310 1311 /* 1312 * vm_object_madvise: 1313 * 1314 * Implements the madvise function at the object/page level. 1315 * 1316 * MADV_WILLNEED (any object) 1317 * 1318 * Activate the specified pages if they are resident. 1319 * 1320 * MADV_DONTNEED (any object) 1321 * 1322 * Deactivate the specified pages if they are resident. 1323 * 1324 * MADV_FREE (OBJT_SWAP objects, OBJ_ONEMAPPING only) 1325 * 1326 * Deactivate and clean the specified pages if they are 1327 * resident. This permits the process to reuse the pages 1328 * without faulting or the kernel to reclaim the pages 1329 * without I/O. 1330 */ 1331 void 1332 vm_object_madvise(vm_object_t object, vm_pindex_t pindex, vm_pindex_t end, 1333 int advice) 1334 { 1335 struct pctrie_iter pages; 1336 vm_pindex_t tpindex; 1337 vm_object_t backing_object, tobject; 1338 vm_page_t m, tm; 1339 1340 if (object == NULL) 1341 return; 1342 1343 vm_page_iter_init(&pages, object); 1344 relookup: 1345 VM_OBJECT_WLOCK(object); 1346 if (!vm_object_advice_applies(object, advice)) { 1347 VM_OBJECT_WUNLOCK(object); 1348 return; 1349 } 1350 for (m = vm_radix_iter_lookup_ge(&pages, pindex); pindex < end; 1351 pindex++) { 1352 tobject = object; 1353 1354 /* 1355 * If the next page isn't resident in the top-level object, we 1356 * need to search the shadow chain. When applying MADV_FREE, we 1357 * take care to release any swap space used to store 1358 * non-resident pages. 1359 */ 1360 if (m == NULL || pindex < m->pindex) { 1361 /* 1362 * Optimize a common case: if the top-level object has 1363 * no backing object, we can skip over the non-resident 1364 * range in constant time. 1365 */ 1366 if (object->backing_object == NULL) { 1367 tpindex = (m != NULL && m->pindex < end) ? 1368 m->pindex : end; 1369 vm_object_madvise_freespace(object, advice, 1370 pindex, tpindex - pindex); 1371 if ((pindex = tpindex) == end) 1372 break; 1373 goto next_page; 1374 } 1375 1376 tpindex = pindex; 1377 do { 1378 vm_object_madvise_freespace(tobject, advice, 1379 tpindex, 1); 1380 /* 1381 * Prepare to search the next object in the 1382 * chain. 1383 */ 1384 backing_object = tobject->backing_object; 1385 if (backing_object == NULL) 1386 goto next_pindex; 1387 VM_OBJECT_WLOCK(backing_object); 1388 tpindex += 1389 OFF_TO_IDX(tobject->backing_object_offset); 1390 if (tobject != object) 1391 VM_OBJECT_WUNLOCK(tobject); 1392 tobject = backing_object; 1393 if (!vm_object_advice_applies(tobject, advice)) 1394 goto next_pindex; 1395 } while ((tm = vm_page_lookup(tobject, tpindex)) == 1396 NULL); 1397 } else { 1398 next_page: 1399 tm = m; 1400 m = vm_radix_iter_step(&pages); 1401 } 1402 1403 /* 1404 * If the page is not in a normal state, skip it. The page 1405 * can not be invalidated while the object lock is held. 1406 */ 1407 if (!vm_page_all_valid(tm) || vm_page_wired(tm)) 1408 goto next_pindex; 1409 KASSERT((tm->flags & PG_FICTITIOUS) == 0, 1410 ("vm_object_madvise: page %p is fictitious", tm)); 1411 KASSERT((tm->oflags & VPO_UNMANAGED) == 0, 1412 ("vm_object_madvise: page %p is not managed", tm)); 1413 if (vm_page_tryxbusy(tm) == 0) { 1414 if (object != tobject) 1415 VM_OBJECT_WUNLOCK(object); 1416 if (advice == MADV_WILLNEED) { 1417 /* 1418 * Reference the page before unlocking and 1419 * sleeping so that the page daemon is less 1420 * likely to reclaim it. 1421 */ 1422 vm_page_aflag_set(tm, PGA_REFERENCED); 1423 } 1424 if (!vm_page_busy_sleep(tm, "madvpo", 0)) 1425 VM_OBJECT_WUNLOCK(tobject); 1426 pctrie_iter_reset(&pages); 1427 goto relookup; 1428 } 1429 vm_page_advise(tm, advice); 1430 vm_page_xunbusy(tm); 1431 vm_object_madvise_freespace(tobject, advice, tm->pindex, 1); 1432 next_pindex: 1433 if (tobject != object) 1434 VM_OBJECT_WUNLOCK(tobject); 1435 } 1436 VM_OBJECT_WUNLOCK(object); 1437 } 1438 1439 /* 1440 * vm_object_shadow: 1441 * 1442 * Create a new object which is backed by the 1443 * specified existing object range. The source 1444 * object reference is deallocated. 1445 * 1446 * The new object and offset into that object 1447 * are returned in the source parameters. 1448 */ 1449 void 1450 vm_object_shadow(vm_object_t *object, vm_ooffset_t *offset, vm_size_t length, 1451 struct ucred *cred, bool shared) 1452 { 1453 vm_object_t source; 1454 vm_object_t result; 1455 1456 source = *object; 1457 1458 /* 1459 * Don't create the new object if the old object isn't shared. 1460 * 1461 * If we hold the only reference we can guarantee that it won't 1462 * increase while we have the map locked. Otherwise the race is 1463 * harmless and we will end up with an extra shadow object that 1464 * will be collapsed later. 1465 */ 1466 if (source != NULL && source->ref_count == 1 && 1467 (source->flags & OBJ_ANON) != 0) 1468 return; 1469 1470 /* 1471 * Allocate a new object with the given length. 1472 */ 1473 result = vm_object_allocate_anon(atop(length), source, cred, length); 1474 1475 /* 1476 * Store the offset into the source object, and fix up the offset into 1477 * the new object. 1478 */ 1479 result->backing_object_offset = *offset; 1480 1481 if (shared || source != NULL) { 1482 VM_OBJECT_WLOCK(result); 1483 1484 /* 1485 * The new object shadows the source object, adding a 1486 * reference to it. Our caller changes his reference 1487 * to point to the new object, removing a reference to 1488 * the source object. Net result: no change of 1489 * reference count, unless the caller needs to add one 1490 * more reference due to forking a shared map entry. 1491 */ 1492 if (shared) { 1493 vm_object_reference_locked(result); 1494 vm_object_clear_flag(result, OBJ_ONEMAPPING); 1495 } 1496 1497 /* 1498 * Try to optimize the result object's page color when 1499 * shadowing in order to maintain page coloring 1500 * consistency in the combined shadowed object. 1501 */ 1502 if (source != NULL) { 1503 vm_object_backing_insert(result, source); 1504 result->domain = source->domain; 1505 #if VM_NRESERVLEVEL > 0 1506 vm_object_set_flag(result, 1507 (source->flags & OBJ_COLORED)); 1508 result->pg_color = (source->pg_color + 1509 OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1510 1)) - 1); 1511 #endif 1512 } 1513 VM_OBJECT_WUNLOCK(result); 1514 } 1515 1516 /* 1517 * Return the new things 1518 */ 1519 *offset = 0; 1520 *object = result; 1521 } 1522 1523 /* 1524 * vm_object_split: 1525 * 1526 * Split the pages in a map entry into a new object. This affords 1527 * easier removal of unused pages, and keeps object inheritance from 1528 * being a negative impact on memory usage. 1529 */ 1530 void 1531 vm_object_split(vm_map_entry_t entry) 1532 { 1533 struct pctrie_iter pages; 1534 vm_page_t m; 1535 vm_object_t orig_object, new_object, backing_object; 1536 vm_pindex_t offidxstart; 1537 vm_size_t size; 1538 1539 orig_object = entry->object.vm_object; 1540 KASSERT((orig_object->flags & OBJ_ONEMAPPING) != 0, 1541 ("vm_object_split: Splitting object with multiple mappings.")); 1542 if ((orig_object->flags & OBJ_ANON) == 0) 1543 return; 1544 if (orig_object->ref_count <= 1) 1545 return; 1546 VM_OBJECT_WUNLOCK(orig_object); 1547 1548 offidxstart = OFF_TO_IDX(entry->offset); 1549 size = atop(entry->end - entry->start); 1550 1551 new_object = vm_object_allocate_anon(size, orig_object, 1552 orig_object->cred, ptoa(size)); 1553 1554 /* 1555 * We must wait for the orig_object to complete any in-progress 1556 * collapse so that the swap blocks are stable below. The 1557 * additional reference on backing_object by new object will 1558 * prevent further collapse operations until split completes. 1559 */ 1560 VM_OBJECT_WLOCK(orig_object); 1561 vm_object_collapse_wait(orig_object); 1562 1563 /* 1564 * At this point, the new object is still private, so the order in 1565 * which the original and new objects are locked does not matter. 1566 */ 1567 VM_OBJECT_WLOCK(new_object); 1568 new_object->domain = orig_object->domain; 1569 backing_object = orig_object->backing_object; 1570 if (backing_object != NULL) { 1571 vm_object_backing_insert_ref(new_object, backing_object); 1572 new_object->backing_object_offset = 1573 orig_object->backing_object_offset + entry->offset; 1574 } 1575 if (orig_object->cred != NULL) { 1576 crhold(orig_object->cred); 1577 KASSERT(orig_object->charge >= ptoa(size), 1578 ("orig_object->charge < 0")); 1579 orig_object->charge -= ptoa(size); 1580 } 1581 1582 /* 1583 * Mark the split operation so that swap_pager_getpages() knows 1584 * that the object is in transition. 1585 */ 1586 vm_object_set_flag(orig_object, OBJ_SPLIT); 1587 vm_page_iter_limit_init(&pages, orig_object, offidxstart + size); 1588 retry: 1589 KASSERT(pctrie_iter_is_reset(&pages), 1590 ("%s: pctrie_iter not reset for retry", __func__)); 1591 for (m = vm_radix_iter_lookup_ge(&pages, offidxstart); m != NULL; 1592 m = vm_radix_iter_step(&pages)) { 1593 /* 1594 * We must wait for pending I/O to complete before we can 1595 * rename the page. 1596 * 1597 * We do not have to VM_PROT_NONE the page as mappings should 1598 * not be changed by this operation. 1599 */ 1600 if (vm_page_tryxbusy(m) == 0) { 1601 VM_OBJECT_WUNLOCK(new_object); 1602 if (vm_page_busy_sleep(m, "spltwt", 0)) 1603 VM_OBJECT_WLOCK(orig_object); 1604 pctrie_iter_reset(&pages); 1605 VM_OBJECT_WLOCK(new_object); 1606 goto retry; 1607 } 1608 1609 /* 1610 * If the page was left invalid, it was likely placed there by 1611 * an incomplete fault. Just remove and ignore. 1612 * 1613 * One other possibility is that the map entry is wired, in 1614 * which case we must hang on to the page to avoid leaking it, 1615 * as the map entry owns the wiring. This case can arise if the 1616 * backing object is truncated by the pager. 1617 */ 1618 if (vm_page_none_valid(m) && entry->wired_count == 0) { 1619 if (vm_page_iter_remove(&pages, m)) 1620 vm_page_free(m); 1621 continue; 1622 } 1623 1624 /* vm_page_iter_rename() will dirty the page if it is valid. */ 1625 if (!vm_page_iter_rename(&pages, m, new_object, m->pindex - 1626 offidxstart)) { 1627 vm_page_xunbusy(m); 1628 VM_OBJECT_WUNLOCK(new_object); 1629 VM_OBJECT_WUNLOCK(orig_object); 1630 vm_radix_wait(); 1631 pctrie_iter_reset(&pages); 1632 VM_OBJECT_WLOCK(orig_object); 1633 VM_OBJECT_WLOCK(new_object); 1634 goto retry; 1635 } 1636 1637 #if VM_NRESERVLEVEL > 0 1638 /* 1639 * If some of the reservation's allocated pages remain with 1640 * the original object, then transferring the reservation to 1641 * the new object is neither particularly beneficial nor 1642 * particularly harmful as compared to leaving the reservation 1643 * with the original object. If, however, all of the 1644 * reservation's allocated pages are transferred to the new 1645 * object, then transferring the reservation is typically 1646 * beneficial. Determining which of these two cases applies 1647 * would be more costly than unconditionally renaming the 1648 * reservation. 1649 */ 1650 vm_reserv_rename(m, new_object, orig_object, offidxstart); 1651 #endif 1652 } 1653 1654 /* 1655 * swap_pager_copy() can sleep, in which case the orig_object's 1656 * and new_object's locks are released and reacquired. 1657 */ 1658 swap_pager_copy(orig_object, new_object, offidxstart, 0); 1659 vm_page_iter_init(&pages, new_object); 1660 VM_RADIX_FOREACH(m, &pages) 1661 vm_page_xunbusy(m); 1662 1663 vm_object_clear_flag(orig_object, OBJ_SPLIT); 1664 VM_OBJECT_WUNLOCK(orig_object); 1665 VM_OBJECT_WUNLOCK(new_object); 1666 entry->object.vm_object = new_object; 1667 entry->offset = 0LL; 1668 vm_object_deallocate(orig_object); 1669 VM_OBJECT_WLOCK(new_object); 1670 } 1671 1672 static vm_page_t 1673 vm_object_collapse_scan_wait(struct pctrie_iter *pages, vm_object_t object, 1674 vm_page_t p) 1675 { 1676 vm_object_t backing_object; 1677 1678 VM_OBJECT_ASSERT_WLOCKED(object); 1679 backing_object = object->backing_object; 1680 VM_OBJECT_ASSERT_WLOCKED(backing_object); 1681 1682 KASSERT(p == NULL || p->object == object || p->object == backing_object, 1683 ("invalid ownership %p %p %p", p, object, backing_object)); 1684 /* The page is only NULL when rename fails. */ 1685 if (p == NULL) { 1686 VM_OBJECT_WUNLOCK(object); 1687 VM_OBJECT_WUNLOCK(backing_object); 1688 vm_radix_wait(); 1689 VM_OBJECT_WLOCK(object); 1690 } else if (p->object == object) { 1691 VM_OBJECT_WUNLOCK(backing_object); 1692 if (vm_page_busy_sleep(p, "vmocol", 0)) 1693 VM_OBJECT_WLOCK(object); 1694 } else { 1695 VM_OBJECT_WUNLOCK(object); 1696 if (!vm_page_busy_sleep(p, "vmocol", 0)) 1697 VM_OBJECT_WUNLOCK(backing_object); 1698 VM_OBJECT_WLOCK(object); 1699 } 1700 VM_OBJECT_WLOCK(backing_object); 1701 vm_page_iter_init(pages, backing_object); 1702 return (vm_radix_iter_lookup_ge(pages, 0)); 1703 } 1704 1705 static void 1706 vm_object_collapse_scan(vm_object_t object) 1707 { 1708 struct pctrie_iter pages; 1709 vm_object_t backing_object; 1710 vm_page_t next, p, pp; 1711 vm_pindex_t backing_offset_index, new_pindex; 1712 1713 VM_OBJECT_ASSERT_WLOCKED(object); 1714 VM_OBJECT_ASSERT_WLOCKED(object->backing_object); 1715 1716 backing_object = object->backing_object; 1717 backing_offset_index = OFF_TO_IDX(object->backing_object_offset); 1718 1719 /* 1720 * Our scan 1721 */ 1722 vm_page_iter_init(&pages, backing_object); 1723 for (p = vm_radix_iter_lookup_ge(&pages, 0); p != NULL; p = next) { 1724 /* 1725 * Check for busy page 1726 */ 1727 if (vm_page_tryxbusy(p) == 0) { 1728 next = vm_object_collapse_scan_wait(&pages, object, p); 1729 continue; 1730 } 1731 1732 KASSERT(object->backing_object == backing_object, 1733 ("vm_object_collapse_scan: backing object mismatch %p != %p", 1734 object->backing_object, backing_object)); 1735 KASSERT(p->object == backing_object, 1736 ("vm_object_collapse_scan: object mismatch %p != %p", 1737 p->object, backing_object)); 1738 1739 if (p->pindex < backing_offset_index || object->size <= 1740 (new_pindex = p->pindex - backing_offset_index)) { 1741 vm_pager_freespace(backing_object, p->pindex, 1); 1742 1743 KASSERT(!pmap_page_is_mapped(p), 1744 ("freeing mapped page %p", p)); 1745 if (vm_page_iter_remove(&pages, p)) 1746 vm_page_free(p); 1747 next = vm_radix_iter_step(&pages); 1748 continue; 1749 } 1750 1751 if (!vm_page_all_valid(p)) { 1752 KASSERT(!pmap_page_is_mapped(p), 1753 ("freeing mapped page %p", p)); 1754 if (vm_page_iter_remove(&pages, p)) 1755 vm_page_free(p); 1756 next = vm_radix_iter_step(&pages); 1757 continue; 1758 } 1759 1760 pp = vm_page_lookup(object, new_pindex); 1761 if (pp != NULL && vm_page_tryxbusy(pp) == 0) { 1762 vm_page_xunbusy(p); 1763 /* 1764 * The page in the parent is busy and possibly not 1765 * (yet) valid. Until its state is finalized by the 1766 * busy bit owner, we can't tell whether it shadows the 1767 * original page. 1768 */ 1769 next = vm_object_collapse_scan_wait(&pages, object, pp); 1770 continue; 1771 } 1772 1773 if (pp != NULL && vm_page_none_valid(pp)) { 1774 /* 1775 * The page was invalid in the parent. Likely placed 1776 * there by an incomplete fault. Just remove and 1777 * ignore. p can replace it. 1778 */ 1779 if (vm_page_remove(pp)) 1780 vm_page_free(pp); 1781 pp = NULL; 1782 } 1783 1784 if (pp != NULL || vm_pager_has_page(object, new_pindex, NULL, 1785 NULL)) { 1786 /* 1787 * The page already exists in the parent OR swap exists 1788 * for this location in the parent. Leave the parent's 1789 * page alone. Destroy the original page from the 1790 * backing object. 1791 */ 1792 vm_pager_freespace(backing_object, p->pindex, 1); 1793 KASSERT(!pmap_page_is_mapped(p), 1794 ("freeing mapped page %p", p)); 1795 if (pp != NULL) 1796 vm_page_xunbusy(pp); 1797 if (vm_page_iter_remove(&pages, p)) 1798 vm_page_free(p); 1799 next = vm_radix_iter_step(&pages); 1800 continue; 1801 } 1802 1803 /* 1804 * Page does not exist in parent, rename the page from the 1805 * backing object to the main object. 1806 * 1807 * If the page was mapped to a process, it can remain mapped 1808 * through the rename. vm_page_iter_rename() will dirty the 1809 * page. 1810 */ 1811 if (!vm_page_iter_rename(&pages, p, object, new_pindex)) { 1812 vm_page_xunbusy(p); 1813 next = vm_object_collapse_scan_wait(&pages, object, 1814 NULL); 1815 continue; 1816 } 1817 1818 /* Use the old pindex to free the right page. */ 1819 vm_pager_freespace(backing_object, new_pindex + 1820 backing_offset_index, 1); 1821 1822 #if VM_NRESERVLEVEL > 0 1823 /* 1824 * Rename the reservation. 1825 */ 1826 vm_reserv_rename(p, object, backing_object, 1827 backing_offset_index); 1828 #endif 1829 vm_page_xunbusy(p); 1830 next = vm_radix_iter_step(&pages); 1831 } 1832 return; 1833 } 1834 1835 /* 1836 * vm_object_collapse: 1837 * 1838 * Collapse an object with the object backing it. 1839 * Pages in the backing object are moved into the 1840 * parent, and the backing object is deallocated. 1841 */ 1842 void 1843 vm_object_collapse(vm_object_t object) 1844 { 1845 vm_object_t backing_object, new_backing_object; 1846 1847 VM_OBJECT_ASSERT_WLOCKED(object); 1848 1849 while (TRUE) { 1850 KASSERT((object->flags & (OBJ_DEAD | OBJ_ANON)) == OBJ_ANON, 1851 ("collapsing invalid object")); 1852 1853 /* 1854 * Wait for the backing_object to finish any pending 1855 * collapse so that the caller sees the shortest possible 1856 * shadow chain. 1857 */ 1858 backing_object = vm_object_backing_collapse_wait(object); 1859 if (backing_object == NULL) 1860 return; 1861 1862 KASSERT(object->ref_count > 0 && 1863 object->ref_count > atomic_load_int(&object->shadow_count), 1864 ("collapse with invalid ref %d or shadow %d count.", 1865 object->ref_count, atomic_load_int(&object->shadow_count))); 1866 KASSERT((backing_object->flags & 1867 (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1868 ("vm_object_collapse: Backing object already collapsing.")); 1869 KASSERT((object->flags & (OBJ_COLLAPSING | OBJ_DEAD)) == 0, 1870 ("vm_object_collapse: object is already collapsing.")); 1871 1872 /* 1873 * We know that we can either collapse the backing object if 1874 * the parent is the only reference to it, or (perhaps) have 1875 * the parent bypass the object if the parent happens to shadow 1876 * all the resident pages in the entire backing object. 1877 */ 1878 if (backing_object->ref_count == 1) { 1879 KASSERT(atomic_load_int(&backing_object->shadow_count) 1880 == 1, 1881 ("vm_object_collapse: shadow_count: %d", 1882 atomic_load_int(&backing_object->shadow_count))); 1883 vm_object_pip_add(object, 1); 1884 vm_object_set_flag(object, OBJ_COLLAPSING); 1885 vm_object_pip_add(backing_object, 1); 1886 vm_object_set_flag(backing_object, OBJ_DEAD); 1887 1888 /* 1889 * If there is exactly one reference to the backing 1890 * object, we can collapse it into the parent. 1891 */ 1892 vm_object_collapse_scan(object); 1893 1894 /* 1895 * Move the pager from backing_object to object. 1896 * 1897 * swap_pager_copy() can sleep, in which case the 1898 * backing_object's and object's locks are released and 1899 * reacquired. 1900 */ 1901 swap_pager_copy(backing_object, object, 1902 OFF_TO_IDX(object->backing_object_offset), TRUE); 1903 1904 /* 1905 * Object now shadows whatever backing_object did. 1906 */ 1907 vm_object_clear_flag(object, OBJ_COLLAPSING); 1908 vm_object_backing_transfer(object, backing_object); 1909 object->backing_object_offset += 1910 backing_object->backing_object_offset; 1911 VM_OBJECT_WUNLOCK(object); 1912 vm_object_pip_wakeup(object); 1913 1914 /* 1915 * Discard backing_object. 1916 * 1917 * Since the backing object has no pages, no pager left, 1918 * and no object references within it, all that is 1919 * necessary is to dispose of it. 1920 */ 1921 KASSERT(backing_object->ref_count == 1, ( 1922 "backing_object %p was somehow re-referenced during collapse!", 1923 backing_object)); 1924 vm_object_pip_wakeup(backing_object); 1925 (void)refcount_release(&backing_object->ref_count); 1926 umtx_shm_object_terminated(backing_object); 1927 vm_object_terminate(backing_object); 1928 counter_u64_add(object_collapses, 1); 1929 VM_OBJECT_WLOCK(object); 1930 } else { 1931 /* 1932 * If we do not entirely shadow the backing object, 1933 * there is nothing we can do so we give up. 1934 * 1935 * The object lock and backing_object lock must not 1936 * be dropped during this sequence. 1937 */ 1938 if (!swap_pager_scan_all_shadowed(object)) { 1939 VM_OBJECT_WUNLOCK(backing_object); 1940 break; 1941 } 1942 1943 /* 1944 * Make the parent shadow the next object in the 1945 * chain. Deallocating backing_object will not remove 1946 * it, since its reference count is at least 2. 1947 */ 1948 vm_object_backing_remove_locked(object); 1949 new_backing_object = backing_object->backing_object; 1950 if (new_backing_object != NULL) { 1951 vm_object_backing_insert_ref(object, 1952 new_backing_object); 1953 object->backing_object_offset += 1954 backing_object->backing_object_offset; 1955 } 1956 1957 /* 1958 * Drop the reference count on backing_object. Since 1959 * its ref_count was at least 2, it will not vanish. 1960 */ 1961 (void)refcount_release(&backing_object->ref_count); 1962 KASSERT(backing_object->ref_count >= 1, ( 1963 "backing_object %p was somehow dereferenced during collapse!", 1964 backing_object)); 1965 VM_OBJECT_WUNLOCK(backing_object); 1966 counter_u64_add(object_bypasses, 1); 1967 } 1968 1969 /* 1970 * Try again with this object's new backing object. 1971 */ 1972 } 1973 } 1974 1975 /* 1976 * vm_object_page_remove: 1977 * 1978 * For the given object, either frees or invalidates each of the 1979 * specified pages. In general, a page is freed. However, if a page is 1980 * wired for any reason other than the existence of a managed, wired 1981 * mapping, then it may be invalidated but not removed from the object. 1982 * Pages are specified by the given range ["start", "end") and the option 1983 * OBJPR_CLEANONLY. As a special case, if "end" is zero, then the range 1984 * extends from "start" to the end of the object. If the option 1985 * OBJPR_CLEANONLY is specified, then only the non-dirty pages within the 1986 * specified range are affected. If the option OBJPR_NOTMAPPED is 1987 * specified, then the pages within the specified range must have no 1988 * mappings. Otherwise, if this option is not specified, any mappings to 1989 * the specified pages are removed before the pages are freed or 1990 * invalidated. 1991 * 1992 * In general, this operation should only be performed on objects that 1993 * contain managed pages. There are, however, two exceptions. First, it 1994 * is performed on the kernel and kmem objects by vm_map_entry_delete(). 1995 * Second, it is used by msync(..., MS_INVALIDATE) to invalidate device- 1996 * backed pages. In both of these cases, the option OBJPR_CLEANONLY must 1997 * not be specified and the option OBJPR_NOTMAPPED must be specified. 1998 * 1999 * The object must be locked. 2000 */ 2001 void 2002 vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, 2003 int options) 2004 { 2005 struct pctrie_iter pages; 2006 vm_page_t p; 2007 2008 VM_OBJECT_ASSERT_WLOCKED(object); 2009 KASSERT((object->flags & OBJ_UNMANAGED) == 0 || 2010 (options & (OBJPR_CLEANONLY | OBJPR_NOTMAPPED)) == OBJPR_NOTMAPPED, 2011 ("vm_object_page_remove: illegal options for object %p", object)); 2012 if (object->resident_page_count == 0) 2013 return; 2014 vm_object_pip_add(object, 1); 2015 vm_page_iter_limit_init(&pages, object, end); 2016 again: 2017 KASSERT(pctrie_iter_is_reset(&pages), 2018 ("%s: pctrie_iter not reset for retry", __func__)); 2019 for (p = vm_radix_iter_lookup_ge(&pages, start); p != NULL; 2020 p = vm_radix_iter_step(&pages)) { 2021 /* 2022 * Skip invalid pages if asked to do so. Try to avoid acquiring 2023 * the busy lock, as some consumers rely on this to avoid 2024 * deadlocks. 2025 * 2026 * A thread may concurrently transition the page from invalid to 2027 * valid using only the busy lock, so the result of this check 2028 * is immediately stale. It is up to consumers to handle this, 2029 * for instance by ensuring that all invalid->valid transitions 2030 * happen with a mutex held, as may be possible for a 2031 * filesystem. 2032 */ 2033 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) 2034 continue; 2035 2036 /* 2037 * If the page is wired for any reason besides the existence 2038 * of managed, wired mappings, then it cannot be freed. For 2039 * example, fictitious pages, which represent device memory, 2040 * are inherently wired and cannot be freed. They can, 2041 * however, be invalidated if the option OBJPR_CLEANONLY is 2042 * not specified. 2043 */ 2044 if (vm_page_tryxbusy(p) == 0) { 2045 if (vm_page_busy_sleep(p, "vmopar", 0)) 2046 VM_OBJECT_WLOCK(object); 2047 pctrie_iter_reset(&pages); 2048 goto again; 2049 } 2050 if ((options & OBJPR_VALIDONLY) != 0 && vm_page_none_valid(p)) { 2051 vm_page_xunbusy(p); 2052 continue; 2053 } 2054 if (vm_page_wired(p)) { 2055 wired: 2056 if ((options & OBJPR_NOTMAPPED) == 0 && 2057 object->ref_count != 0) 2058 pmap_remove_all(p); 2059 if ((options & OBJPR_CLEANONLY) == 0) { 2060 vm_page_invalid(p); 2061 vm_page_undirty(p); 2062 } 2063 vm_page_xunbusy(p); 2064 continue; 2065 } 2066 KASSERT((p->flags & PG_FICTITIOUS) == 0, 2067 ("vm_object_page_remove: page %p is fictitious", p)); 2068 if ((options & OBJPR_CLEANONLY) != 0 && 2069 !vm_page_none_valid(p)) { 2070 if ((options & OBJPR_NOTMAPPED) == 0 && 2071 object->ref_count != 0 && 2072 !vm_page_try_remove_write(p)) 2073 goto wired; 2074 if (p->dirty != 0) { 2075 vm_page_xunbusy(p); 2076 continue; 2077 } 2078 } 2079 if ((options & OBJPR_NOTMAPPED) == 0 && 2080 object->ref_count != 0 && !vm_page_try_remove_all(p)) 2081 goto wired; 2082 vm_page_iter_free(&pages, p); 2083 } 2084 vm_object_pip_wakeup(object); 2085 2086 vm_pager_freespace(object, start, (end == 0 ? object->size : end) - 2087 start); 2088 } 2089 2090 /* 2091 * vm_object_page_noreuse: 2092 * 2093 * For the given object, attempt to move the specified pages to 2094 * the head of the inactive queue. This bypasses regular LRU 2095 * operation and allows the pages to be reused quickly under memory 2096 * pressure. If a page is wired for any reason, then it will not 2097 * be queued. Pages are specified by the range ["start", "end"). 2098 * As a special case, if "end" is zero, then the range extends from 2099 * "start" to the end of the object. 2100 * 2101 * This operation should only be performed on objects that 2102 * contain non-fictitious, managed pages. 2103 * 2104 * The object must be locked. 2105 */ 2106 void 2107 vm_object_page_noreuse(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2108 { 2109 struct pctrie_iter pages; 2110 vm_page_t p; 2111 2112 VM_OBJECT_ASSERT_LOCKED(object); 2113 KASSERT((object->flags & (OBJ_FICTITIOUS | OBJ_UNMANAGED)) == 0, 2114 ("vm_object_page_noreuse: illegal object %p", object)); 2115 if (object->resident_page_count == 0) 2116 return; 2117 2118 vm_page_iter_limit_init(&pages, object, end); 2119 VM_RADIX_FOREACH_FROM(p, &pages, start) 2120 vm_page_deactivate_noreuse(p); 2121 } 2122 2123 /* 2124 * Populate the specified range of the object with valid pages. Returns 2125 * TRUE if the range is successfully populated and FALSE otherwise. 2126 * 2127 * Note: This function should be optimized to pass a larger array of 2128 * pages to vm_pager_get_pages() before it is applied to a non- 2129 * OBJT_DEVICE object. 2130 * 2131 * The object must be locked. 2132 */ 2133 boolean_t 2134 vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) 2135 { 2136 struct pctrie_iter pages; 2137 vm_page_t m; 2138 vm_pindex_t pindex; 2139 int rv; 2140 2141 vm_page_iter_init(&pages, object); 2142 VM_OBJECT_ASSERT_WLOCKED(object); 2143 for (pindex = start; pindex < end; pindex++) { 2144 rv = vm_page_grab_valid_iter(&m, object, &pages, pindex, 2145 VM_ALLOC_NORMAL); 2146 if (rv != VM_PAGER_OK) 2147 break; 2148 2149 /* 2150 * Keep "m" busy because a subsequent iteration may unlock 2151 * the object. 2152 */ 2153 } 2154 if (pindex > start) { 2155 pages.limit = pindex; 2156 VM_RADIX_FORALL_FROM(m, &pages, start) 2157 vm_page_xunbusy(m); 2158 } 2159 return (pindex == end); 2160 } 2161 2162 /* 2163 * Routine: vm_object_coalesce 2164 * Function: Coalesces two objects backing up adjoining 2165 * regions of memory into a single object. 2166 * 2167 * returns TRUE if objects were combined. 2168 * 2169 * NOTE: Only works at the moment if the second object is NULL - 2170 * if it's not, which object do we lock first? 2171 * 2172 * Parameters: 2173 * prev_object First object to coalesce 2174 * prev_offset Offset into prev_object 2175 * prev_size Size of reference to prev_object 2176 * next_size Size of reference to the second object 2177 * reserved Indicator that extension region has 2178 * swap accounted for 2179 * 2180 * Conditions: 2181 * The object must *not* be locked. 2182 */ 2183 boolean_t 2184 vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, 2185 vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) 2186 { 2187 vm_pindex_t next_pindex; 2188 2189 if (prev_object == NULL) 2190 return (TRUE); 2191 if ((prev_object->flags & OBJ_ANON) == 0) 2192 return (FALSE); 2193 2194 VM_OBJECT_WLOCK(prev_object); 2195 /* 2196 * Try to collapse the object first. 2197 */ 2198 vm_object_collapse(prev_object); 2199 2200 /* 2201 * Can't coalesce if: . more than one reference . paged out . shadows 2202 * another object . has a copy elsewhere (any of which mean that the 2203 * pages not mapped to prev_entry may be in use anyway) 2204 */ 2205 if (prev_object->backing_object != NULL) { 2206 VM_OBJECT_WUNLOCK(prev_object); 2207 return (FALSE); 2208 } 2209 2210 prev_size >>= PAGE_SHIFT; 2211 next_size >>= PAGE_SHIFT; 2212 next_pindex = OFF_TO_IDX(prev_offset) + prev_size; 2213 2214 if (prev_object->ref_count > 1 && 2215 prev_object->size != next_pindex && 2216 (prev_object->flags & OBJ_ONEMAPPING) == 0) { 2217 VM_OBJECT_WUNLOCK(prev_object); 2218 return (FALSE); 2219 } 2220 2221 /* 2222 * Account for the charge. 2223 */ 2224 if (prev_object->cred != NULL) { 2225 /* 2226 * If prev_object was charged, then this mapping, 2227 * although not charged now, may become writable 2228 * later. Non-NULL cred in the object would prevent 2229 * swap reservation during enabling of the write 2230 * access, so reserve swap now. Failed reservation 2231 * cause allocation of the separate object for the map 2232 * entry, and swap reservation for this entry is 2233 * managed in appropriate time. 2234 */ 2235 if (!reserved && !swap_reserve_by_cred(ptoa(next_size), 2236 prev_object->cred)) { 2237 VM_OBJECT_WUNLOCK(prev_object); 2238 return (FALSE); 2239 } 2240 prev_object->charge += ptoa(next_size); 2241 } 2242 2243 /* 2244 * Remove any pages that may still be in the object from a previous 2245 * deallocation. 2246 */ 2247 if (next_pindex < prev_object->size) { 2248 vm_object_page_remove(prev_object, next_pindex, next_pindex + 2249 next_size, 0); 2250 #if 0 2251 if (prev_object->cred != NULL) { 2252 KASSERT(prev_object->charge >= 2253 ptoa(prev_object->size - next_pindex), 2254 ("object %p overcharged 1 %jx %jx", prev_object, 2255 (uintmax_t)next_pindex, (uintmax_t)next_size)); 2256 prev_object->charge -= ptoa(prev_object->size - 2257 next_pindex); 2258 } 2259 #endif 2260 } 2261 2262 /* 2263 * Extend the object if necessary. 2264 */ 2265 if (next_pindex + next_size > prev_object->size) 2266 prev_object->size = next_pindex + next_size; 2267 2268 VM_OBJECT_WUNLOCK(prev_object); 2269 return (TRUE); 2270 } 2271 2272 /* 2273 * Fill in the m_dst array with up to *rbehind optional pages before m_src[0] 2274 * and up to *rahead optional pages after m_src[count - 1]. In both cases, stop 2275 * the filling-in short on encountering a cached page, an object boundary limit, 2276 * or an allocation error. Update *rbehind and *rahead to indicate the number 2277 * of pages allocated. Copy elements of m_src into array elements from 2278 * m_dst[*rbehind] to m_dst[*rbehind + count -1]. 2279 */ 2280 void 2281 vm_object_prepare_buf_pages(vm_object_t object, vm_page_t *ma_dst, int count, 2282 int *rbehind, int *rahead, vm_page_t *ma_src) 2283 { 2284 struct pctrie_iter pages; 2285 vm_pindex_t pindex; 2286 vm_page_t m, mpred, msucc; 2287 2288 vm_page_iter_init(&pages, object); 2289 VM_OBJECT_ASSERT_LOCKED(object); 2290 if (*rbehind != 0) { 2291 m = ma_src[0]; 2292 pindex = m->pindex; 2293 mpred = vm_radix_iter_lookup_lt(&pages, pindex); 2294 *rbehind = MIN(*rbehind, 2295 pindex - (mpred != NULL ? mpred->pindex + 1 : 0)); 2296 /* Stepping backward from pindex, mpred doesn't change. */ 2297 for (int i = 0; i < *rbehind; i++) { 2298 m = vm_page_alloc_after(object, &pages, pindex - i - 1, 2299 VM_ALLOC_NORMAL, mpred); 2300 if (m == NULL) { 2301 /* Shift the array. */ 2302 for (int j = 0; j < i; j++) 2303 ma_dst[j] = ma_dst[j + *rbehind - i]; 2304 *rbehind = i; 2305 *rahead = 0; 2306 break; 2307 } 2308 ma_dst[*rbehind - i - 1] = m; 2309 } 2310 } 2311 for (int i = 0; i < count; i++) 2312 ma_dst[*rbehind + i] = ma_src[i]; 2313 if (*rahead != 0) { 2314 m = ma_src[count - 1]; 2315 pindex = m->pindex + 1; 2316 msucc = vm_radix_iter_lookup_ge(&pages, pindex); 2317 *rahead = MIN(*rahead, 2318 (msucc != NULL ? msucc->pindex : object->size) - pindex); 2319 mpred = m; 2320 for (int i = 0; i < *rahead; i++) { 2321 m = vm_page_alloc_after(object, &pages, pindex + i, 2322 VM_ALLOC_NORMAL, mpred); 2323 if (m == NULL) { 2324 *rahead = i; 2325 break; 2326 } 2327 ma_dst[*rbehind + count + i] = mpred = m; 2328 } 2329 } 2330 } 2331 2332 void 2333 vm_object_set_writeable_dirty_(vm_object_t object) 2334 { 2335 atomic_add_int(&object->generation, 1); 2336 } 2337 2338 bool 2339 vm_object_mightbedirty_(vm_object_t object) 2340 { 2341 return (object->generation != object->cleangeneration); 2342 } 2343 2344 /* 2345 * vm_object_unwire: 2346 * 2347 * For each page offset within the specified range of the given object, 2348 * find the highest-level page in the shadow chain and unwire it. A page 2349 * must exist at every page offset, and the highest-level page must be 2350 * wired. 2351 */ 2352 void 2353 vm_object_unwire(vm_object_t object, vm_ooffset_t offset, vm_size_t length, 2354 uint8_t queue) 2355 { 2356 struct pctrie_iter pages; 2357 vm_object_t tobject, t1object; 2358 vm_page_t m, tm; 2359 vm_pindex_t end_pindex, pindex, tpindex; 2360 int depth, locked_depth; 2361 2362 KASSERT((offset & PAGE_MASK) == 0, 2363 ("vm_object_unwire: offset is not page aligned")); 2364 KASSERT((length & PAGE_MASK) == 0, 2365 ("vm_object_unwire: length is not a multiple of PAGE_SIZE")); 2366 /* The wired count of a fictitious page never changes. */ 2367 if ((object->flags & OBJ_FICTITIOUS) != 0) 2368 return; 2369 pindex = OFF_TO_IDX(offset); 2370 end_pindex = pindex + atop(length); 2371 vm_page_iter_init(&pages, object); 2372 again: 2373 locked_depth = 1; 2374 VM_OBJECT_RLOCK(object); 2375 m = vm_radix_iter_lookup_ge(&pages, pindex); 2376 while (pindex < end_pindex) { 2377 if (m == NULL || pindex < m->pindex) { 2378 /* 2379 * The first object in the shadow chain doesn't 2380 * contain a page at the current index. Therefore, 2381 * the page must exist in a backing object. 2382 */ 2383 tobject = object; 2384 tpindex = pindex; 2385 depth = 0; 2386 do { 2387 tpindex += 2388 OFF_TO_IDX(tobject->backing_object_offset); 2389 tobject = tobject->backing_object; 2390 KASSERT(tobject != NULL, 2391 ("vm_object_unwire: missing page")); 2392 if ((tobject->flags & OBJ_FICTITIOUS) != 0) 2393 goto next_page; 2394 depth++; 2395 if (depth == locked_depth) { 2396 locked_depth++; 2397 VM_OBJECT_RLOCK(tobject); 2398 } 2399 } while ((tm = vm_page_lookup(tobject, tpindex)) == 2400 NULL); 2401 } else { 2402 tm = m; 2403 m = vm_radix_iter_step(&pages); 2404 } 2405 if (vm_page_trysbusy(tm) == 0) { 2406 for (tobject = object; locked_depth >= 1; 2407 locked_depth--) { 2408 t1object = tobject->backing_object; 2409 if (tm->object != tobject) 2410 VM_OBJECT_RUNLOCK(tobject); 2411 tobject = t1object; 2412 } 2413 tobject = tm->object; 2414 if (!vm_page_busy_sleep(tm, "unwbo", 2415 VM_ALLOC_IGN_SBUSY)) 2416 VM_OBJECT_RUNLOCK(tobject); 2417 pctrie_iter_reset(&pages); 2418 goto again; 2419 } 2420 vm_page_unwire(tm, queue); 2421 vm_page_sunbusy(tm); 2422 next_page: 2423 pindex++; 2424 } 2425 /* Release the accumulated object locks. */ 2426 for (tobject = object; locked_depth >= 1; locked_depth--) { 2427 t1object = tobject->backing_object; 2428 VM_OBJECT_RUNLOCK(tobject); 2429 tobject = t1object; 2430 } 2431 } 2432 2433 /* 2434 * Return the vnode for the given object, or NULL if none exists. 2435 * For tmpfs objects, the function may return NULL if there is 2436 * no vnode allocated at the time of the call. 2437 */ 2438 struct vnode * 2439 vm_object_vnode(vm_object_t object) 2440 { 2441 struct vnode *vp; 2442 2443 VM_OBJECT_ASSERT_LOCKED(object); 2444 vm_pager_getvp(object, &vp, NULL); 2445 return (vp); 2446 } 2447 2448 /* 2449 * Busy the vm object. This prevents new pages belonging to the object from 2450 * becoming busy. Existing pages persist as busy. Callers are responsible 2451 * for checking page state before proceeding. 2452 */ 2453 void 2454 vm_object_busy(vm_object_t obj) 2455 { 2456 2457 VM_OBJECT_ASSERT_LOCKED(obj); 2458 2459 blockcount_acquire(&obj->busy, 1); 2460 /* The fence is required to order loads of page busy. */ 2461 atomic_thread_fence_acq_rel(); 2462 } 2463 2464 void 2465 vm_object_unbusy(vm_object_t obj) 2466 { 2467 2468 blockcount_release(&obj->busy, 1); 2469 } 2470 2471 void 2472 vm_object_busy_wait(vm_object_t obj, const char *wmesg) 2473 { 2474 2475 VM_OBJECT_ASSERT_UNLOCKED(obj); 2476 2477 (void)blockcount_sleep(&obj->busy, NULL, wmesg, PVM); 2478 } 2479 2480 /* 2481 * This function aims to determine if the object is mapped, 2482 * specifically, if it is referenced by a vm_map_entry. Because 2483 * objects occasionally acquire transient references that do not 2484 * represent a mapping, the method used here is inexact. However, it 2485 * has very low overhead and is good enough for the advisory 2486 * vm.vmtotal sysctl. 2487 */ 2488 bool 2489 vm_object_is_active(vm_object_t obj) 2490 { 2491 2492 return (obj->ref_count > atomic_load_int(&obj->shadow_count)); 2493 } 2494 2495 static int 2496 vm_object_list_handler(struct sysctl_req *req, bool swap_only) 2497 { 2498 struct pctrie_iter pages; 2499 struct kinfo_vmobject *kvo; 2500 char *fullpath, *freepath; 2501 struct vnode *vp; 2502 struct vattr va; 2503 vm_object_t obj; 2504 vm_page_t m; 2505 u_long sp; 2506 int count, error; 2507 key_t key; 2508 unsigned short seq; 2509 bool want_path; 2510 2511 if (req->oldptr == NULL) { 2512 /* 2513 * If an old buffer has not been provided, generate an 2514 * estimate of the space needed for a subsequent call. 2515 */ 2516 mtx_lock(&vm_object_list_mtx); 2517 count = 0; 2518 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2519 if (obj->type == OBJT_DEAD) 2520 continue; 2521 count++; 2522 } 2523 mtx_unlock(&vm_object_list_mtx); 2524 return (SYSCTL_OUT(req, NULL, sizeof(struct kinfo_vmobject) * 2525 count * 11 / 10)); 2526 } 2527 2528 want_path = !(swap_only || jailed(curthread->td_ucred)); 2529 kvo = malloc(sizeof(*kvo), M_TEMP, M_WAITOK | M_ZERO); 2530 error = 0; 2531 2532 /* 2533 * VM objects are type stable and are never removed from the 2534 * list once added. This allows us to safely read obj->object_list 2535 * after reacquiring the VM object lock. 2536 */ 2537 mtx_lock(&vm_object_list_mtx); 2538 TAILQ_FOREACH(obj, &vm_object_list, object_list) { 2539 if (obj->type == OBJT_DEAD || 2540 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) 2541 continue; 2542 VM_OBJECT_RLOCK(obj); 2543 if (obj->type == OBJT_DEAD || 2544 (swap_only && (obj->flags & (OBJ_ANON | OBJ_SWAP)) == 0)) { 2545 VM_OBJECT_RUNLOCK(obj); 2546 continue; 2547 } 2548 mtx_unlock(&vm_object_list_mtx); 2549 kvo->kvo_size = ptoa(obj->size); 2550 kvo->kvo_resident = obj->resident_page_count; 2551 kvo->kvo_ref_count = obj->ref_count; 2552 kvo->kvo_shadow_count = atomic_load_int(&obj->shadow_count); 2553 kvo->kvo_memattr = obj->memattr; 2554 kvo->kvo_active = 0; 2555 kvo->kvo_inactive = 0; 2556 kvo->kvo_flags = 0; 2557 if (!swap_only) { 2558 vm_page_iter_init(&pages, obj); 2559 VM_RADIX_FOREACH(m, &pages) { 2560 /* 2561 * A page may belong to the object but be 2562 * dequeued and set to PQ_NONE while the 2563 * object lock is not held. This makes the 2564 * reads of m->queue below racy, and we do not 2565 * count pages set to PQ_NONE. However, this 2566 * sysctl is only meant to give an 2567 * approximation of the system anyway. 2568 */ 2569 if (vm_page_active(m)) 2570 kvo->kvo_active++; 2571 else if (vm_page_inactive(m)) 2572 kvo->kvo_inactive++; 2573 else if (vm_page_in_laundry(m)) 2574 kvo->kvo_laundry++; 2575 } 2576 } 2577 2578 kvo->kvo_vn_fileid = 0; 2579 kvo->kvo_vn_fsid = 0; 2580 kvo->kvo_vn_fsid_freebsd11 = 0; 2581 freepath = NULL; 2582 fullpath = ""; 2583 vp = NULL; 2584 kvo->kvo_type = vm_object_kvme_type(obj, want_path ? &vp : 2585 NULL); 2586 if (vp != NULL) { 2587 vref(vp); 2588 } else if ((obj->flags & OBJ_ANON) != 0) { 2589 MPASS(kvo->kvo_type == KVME_TYPE_SWAP); 2590 kvo->kvo_me = (uintptr_t)obj; 2591 /* tmpfs objs are reported as vnodes */ 2592 kvo->kvo_backing_obj = (uintptr_t)obj->backing_object; 2593 sp = swap_pager_swapped_pages(obj); 2594 kvo->kvo_swapped = sp > UINT32_MAX ? UINT32_MAX : sp; 2595 } 2596 if (obj->type == OBJT_DEVICE || obj->type == OBJT_MGTDEVICE) { 2597 cdev_pager_get_path(obj, kvo->kvo_path, 2598 sizeof(kvo->kvo_path)); 2599 } 2600 VM_OBJECT_RUNLOCK(obj); 2601 if ((obj->flags & OBJ_SYSVSHM) != 0) { 2602 kvo->kvo_flags |= KVMO_FLAG_SYSVSHM; 2603 shmobjinfo(obj, &key, &seq); 2604 kvo->kvo_vn_fileid = key; 2605 kvo->kvo_vn_fsid_freebsd11 = seq; 2606 } 2607 if ((obj->flags & OBJ_POSIXSHM) != 0) { 2608 kvo->kvo_flags |= KVMO_FLAG_POSIXSHM; 2609 shm_get_path(obj, kvo->kvo_path, 2610 sizeof(kvo->kvo_path)); 2611 } 2612 if (vp != NULL) { 2613 vn_fullpath(vp, &fullpath, &freepath); 2614 vn_lock(vp, LK_SHARED | LK_RETRY); 2615 if (VOP_GETATTR(vp, &va, curthread->td_ucred) == 0) { 2616 kvo->kvo_vn_fileid = va.va_fileid; 2617 kvo->kvo_vn_fsid = va.va_fsid; 2618 kvo->kvo_vn_fsid_freebsd11 = va.va_fsid; 2619 /* truncate */ 2620 } 2621 vput(vp); 2622 strlcpy(kvo->kvo_path, fullpath, sizeof(kvo->kvo_path)); 2623 free(freepath, M_TEMP); 2624 } 2625 2626 /* Pack record size down */ 2627 kvo->kvo_structsize = offsetof(struct kinfo_vmobject, kvo_path) 2628 + strlen(kvo->kvo_path) + 1; 2629 kvo->kvo_structsize = roundup(kvo->kvo_structsize, 2630 sizeof(uint64_t)); 2631 error = SYSCTL_OUT(req, kvo, kvo->kvo_structsize); 2632 maybe_yield(); 2633 mtx_lock(&vm_object_list_mtx); 2634 if (error) 2635 break; 2636 } 2637 mtx_unlock(&vm_object_list_mtx); 2638 free(kvo, M_TEMP); 2639 return (error); 2640 } 2641 2642 static int 2643 sysctl_vm_object_list(SYSCTL_HANDLER_ARGS) 2644 { 2645 return (vm_object_list_handler(req, false)); 2646 } 2647 2648 SYSCTL_PROC(_vm, OID_AUTO, objects, CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | 2649 CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_object_list, "S,kinfo_vmobject", 2650 "List of VM objects"); 2651 2652 static int 2653 sysctl_vm_object_list_swap(SYSCTL_HANDLER_ARGS) 2654 { 2655 return (vm_object_list_handler(req, true)); 2656 } 2657 2658 /* 2659 * This sysctl returns list of the anonymous or swap objects. Intent 2660 * is to provide stripped optimized list useful to analyze swap use. 2661 * Since technically non-swap (default) objects participate in the 2662 * shadow chains, and are converted to swap type as needed by swap 2663 * pager, we must report them. 2664 */ 2665 SYSCTL_PROC(_vm, OID_AUTO, swap_objects, 2666 CTLTYPE_STRUCT | CTLFLAG_RW | CTLFLAG_SKIP | CTLFLAG_MPSAFE, NULL, 0, 2667 sysctl_vm_object_list_swap, "S,kinfo_vmobject", 2668 "List of swap VM objects"); 2669 2670 #include "opt_ddb.h" 2671 #ifdef DDB 2672 #include <sys/kernel.h> 2673 2674 #include <sys/cons.h> 2675 2676 #include <ddb/ddb.h> 2677 2678 static int 2679 _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) 2680 { 2681 vm_map_t tmpm; 2682 vm_map_entry_t tmpe; 2683 vm_object_t obj; 2684 2685 if (map == 0) 2686 return 0; 2687 2688 if (entry == 0) { 2689 VM_MAP_ENTRY_FOREACH(tmpe, map) { 2690 if (_vm_object_in_map(map, object, tmpe)) { 2691 return 1; 2692 } 2693 } 2694 } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { 2695 tmpm = entry->object.sub_map; 2696 VM_MAP_ENTRY_FOREACH(tmpe, tmpm) { 2697 if (_vm_object_in_map(tmpm, object, tmpe)) { 2698 return 1; 2699 } 2700 } 2701 } else if ((obj = entry->object.vm_object) != NULL) { 2702 for (; obj; obj = obj->backing_object) 2703 if (obj == object) { 2704 return 1; 2705 } 2706 } 2707 return 0; 2708 } 2709 2710 static int 2711 vm_object_in_map(vm_object_t object) 2712 { 2713 struct proc *p; 2714 2715 /* sx_slock(&allproc_lock); */ 2716 FOREACH_PROC_IN_SYSTEM(p) { 2717 if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) 2718 continue; 2719 if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { 2720 /* sx_sunlock(&allproc_lock); */ 2721 return 1; 2722 } 2723 } 2724 /* sx_sunlock(&allproc_lock); */ 2725 if (_vm_object_in_map(kernel_map, object, 0)) 2726 return 1; 2727 return 0; 2728 } 2729 2730 DB_SHOW_COMMAND_FLAGS(vmochk, vm_object_check, DB_CMD_MEMSAFE) 2731 { 2732 vm_object_t object; 2733 2734 /* 2735 * make sure that internal objs are in a map somewhere 2736 * and none have zero ref counts. 2737 */ 2738 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2739 if ((object->flags & OBJ_ANON) != 0) { 2740 if (object->ref_count == 0) { 2741 db_printf( 2742 "vmochk: internal obj has zero ref count: %lu\n", 2743 (u_long)object->size); 2744 } 2745 if (!vm_object_in_map(object)) { 2746 db_printf( 2747 "vmochk: internal obj is not in a map: " 2748 "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", 2749 object->ref_count, (u_long)object->size, 2750 (u_long)object->size, 2751 (void *)object->backing_object); 2752 } 2753 } 2754 if (db_pager_quit) 2755 return; 2756 } 2757 } 2758 2759 /* 2760 * vm_object_print: [ debug ] 2761 */ 2762 DB_SHOW_COMMAND(object, vm_object_print_static) 2763 { 2764 struct pctrie_iter pages; 2765 /* XXX convert args. */ 2766 vm_object_t object = (vm_object_t)addr; 2767 boolean_t full = have_addr; 2768 2769 vm_page_t p; 2770 2771 /* XXX count is an (unused) arg. Avoid shadowing it. */ 2772 #define count was_count 2773 2774 int count; 2775 2776 if (object == NULL) 2777 return; 2778 2779 db_iprintf("Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x", 2780 object, (int)object->type, (uintmax_t)object->size, 2781 object->resident_page_count, object->ref_count, object->flags); 2782 db_iprintf(" ruid %d charge %jx\n", 2783 object->cred ? object->cred->cr_ruid : -1, 2784 (uintmax_t)object->charge); 2785 db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", 2786 atomic_load_int(&object->shadow_count), 2787 object->backing_object ? object->backing_object->ref_count : 0, 2788 object->backing_object, (uintmax_t)object->backing_object_offset); 2789 2790 if (!full) 2791 return; 2792 2793 db_indent += 2; 2794 count = 0; 2795 vm_page_iter_init(&pages, object); 2796 VM_RADIX_FOREACH(p, &pages) { 2797 if (count == 0) 2798 db_iprintf("memory:="); 2799 else if (count == 6) { 2800 db_printf("\n"); 2801 db_iprintf(" ..."); 2802 count = 0; 2803 } else 2804 db_printf(","); 2805 count++; 2806 2807 db_printf("(off=0x%jx,page=0x%jx)", 2808 (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); 2809 2810 if (db_pager_quit) 2811 break; 2812 } 2813 if (count != 0) 2814 db_printf("\n"); 2815 db_indent -= 2; 2816 } 2817 2818 /* XXX. */ 2819 #undef count 2820 2821 /* XXX need this non-static entry for calling from vm_map_print. */ 2822 void 2823 vm_object_print( 2824 /* db_expr_t */ long addr, 2825 boolean_t have_addr, 2826 /* db_expr_t */ long count, 2827 char *modif) 2828 { 2829 vm_object_print_static(addr, have_addr, count, modif); 2830 } 2831 2832 DB_SHOW_COMMAND_FLAGS(vmopag, vm_object_print_pages, DB_CMD_MEMSAFE) 2833 { 2834 struct pctrie_iter pages; 2835 vm_object_t object; 2836 vm_page_t m, start_m; 2837 int rcount; 2838 2839 TAILQ_FOREACH(object, &vm_object_list, object_list) { 2840 db_printf("new object: %p\n", (void *)object); 2841 if (db_pager_quit) 2842 return; 2843 start_m = NULL; 2844 vm_page_iter_init(&pages, object); 2845 VM_RADIX_FOREACH(m, &pages) { 2846 if (start_m == NULL) { 2847 start_m = m; 2848 rcount = 0; 2849 } else if (start_m->pindex + rcount != m->pindex || 2850 VM_PAGE_TO_PHYS(start_m) + ptoa(rcount) != 2851 VM_PAGE_TO_PHYS(m)) { 2852 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2853 (long)start_m->pindex, rcount, 2854 (long)VM_PAGE_TO_PHYS(start_m)); 2855 if (db_pager_quit) 2856 return; 2857 start_m = m; 2858 rcount = 0; 2859 } 2860 rcount++; 2861 } 2862 if (start_m != NULL) { 2863 db_printf(" index(%ld)run(%d)pa(0x%lx)\n", 2864 (long)start_m->pindex, rcount, 2865 (long)VM_PAGE_TO_PHYS(start_m)); 2866 if (db_pager_quit) 2867 return; 2868 } 2869 } 2870 } 2871 #endif /* DDB */ 2872